Flame retarded housing for electronic apparatus are normally considered a necessity by electronic apparatus manufacturers to protect against the risk of liability should a fire occur. To meet this need, housings have been fabricated from ABS compositions incorporating brominated fire retardancy additives such as octabromodiphenyl oxide, decabromodiphenyl oxide and bis(tribromophenoxy)ethane, usually in combination with antimony oxide. These brominated additives are not generally considered UV stable, and compositions containing UV unstable additives, when exposed to fluorescent light or other source of ultraviolet radiation, yellow to an undesirable degree. The conventional brominated additives also are disadvantageous in forming dioxin (which is considered to be hazardous) when they burn and in lowering the heat distortion temperature of ABS.
Diels-Alder adduct of 2 moles of chlorocyclopentadiene and 1 mole of cyclooctadiene, a commercially available flame retarder for use in polymers, has been added in small amounts to ABS in substitution for conventional brominated additives in Japan but the product obtained does not have the highest flammability rating and has poor impact strength.
It is an object herein to provide a UV stable, flame retarded ABS composition suitable for use for housings for electronic apparatus or other analogous use.
As used herein, the term "UV stable" means an increase in Yellowness Index of less than 10 between original and seven day readings in testing according to ASTM Procedure No. 1925.
As used herein, the term "impact resistant" means an Izod Impact Strength in foot-pounds per inch of notch as determined on 1/8 inch samples by ASTM Test D256, of at least 2.0.
As used herein the term "flame retarded" means a flammability classification of V-1 or V-0 as determined in Underwriters Laboratories Inc. Test UL94 (third edition) on 1/8" samples.